The test, known as the wet dress rehearsal, has been adapted in response to a problem encountered during the third attempt at the weekend. Engineers located a non-functioning helium non-return valve. The valve is difficult to reach while the rocket is on the launch pad, but can be replaced or repaired later. The modified version of the wet dress rehearsal is necessary to ensure the safety of the rocket flight material. The sun is used to clean the engine before loading an extremely cold propellant – the liquid rehearsal in a wet dress – when refueling. Non-return valves allow gas or liquid to flow in one direction to prevent reverse flow. In this case, the non-functioning part is about 3 inches long and prevents the sun from flowing behind the rocket. When the rocket core tank starts on Thursday, the modified test will remove the valve strain and the upper stage of the rocket with minimal propulsion functions. Previously, the team had planned to fully supply the core and the upper stages of the rocket, but the valve problem prevents this step from taking place during this test. The results of this test will determine if more tests need to be done before launch. “I’m pretty sure we’ll have a good test on Thursday with the modified procedures,” John Blevins, chief SLS engineer at NASA ‘s Marshall Space Flight Center in Huntsville, Alabama, told a news conference Monday. “I can not say that I am happy to have a broken part, but I’m glad we caught it when we did it before we started any surgery that would jeopardize the broken part. That’s why we do thorough tests.” The wet dress rehearsal simulates each launch step without the rocket actually leaving the launch site. This includes powering the SLS rocket and the Orion spacecraft, loading supercool propellant into the rocket tanks, performing a full launch simulation countdown, resetting the countdown clock, and draining the drains. It will start on Tuesday around 5 p.m. ET with the call to the stations, which is a check-in with each group associated with a launch to say that the test has begun. Once this test is complete, the Artemis I rocket will be flown back to the Vehicle Assembly Building at the Kennedy Space Center in Florida, where teams can analyze the valve and replace it if necessary. The previous three wet dress rehearsals have already provided valuable knowledge for the team, officials said, although they have addressed a number of issues. “We’ve completed many of the test requirements we needed to get out of the wet-dressing business,” said Tom Whitmeyer, a deputy research fellow at NASA headquarters, during a news conference Monday. “We have a few more to reach on Thursday. The mega moon rocket is in excellent condition and we are dealing with it very carefully.” Although the exact issues identified during the test attempts were not expected, they are part of the process of testing a new missile. “Every new rocket that appears in a new program like this goes through these updates and understanding rocket performance,” Whitmeyer said. “And that’s the kind of thing we’re going through right now.” “I can say that these are probably not the last challenges we will face,” said Mike Sarafin, Artemis’s director of mission at NASA headquarters, during the conference. “But I’m sure we have the right team in place and the ability to rally around these problems and overcome them is something we are proud of.” The results of the wet dress rehearsal will determine when the unpaid Artemis A will be launched on a mission that transcends the moon and returns to Earth. This mission will launch NASA’s Artemis program, which is expected to return humans to the Moon and land the first woman and the first colored person on the lunar surface by 2025. Current launch window features include June 6 to June 16, June 29 to July 17 and July 26 to August 9, Sarafin said.
